Abstract: An electrophoretically pure protease , named as OP-I, was obtained from the digestive tract of Octopus vulgaris by ammonium sulfate precipitation, cellulose CM-52 cation-exchange chromatography, DEAE-Sephadex A50 anion-exchange chromatography and SDS-PAGE. Its properties were also characterized. The results showed that the molecular weight of the protease was 80.5 kD and its optimal reaction temperature and pH were 55－60 ℃ and 7－9, respectively. OP-I could be completely inhibited by EDTA, a metalloproteinase inhibitor. In contrast, Mn2+, Ca2+ and Mg2+could stimulate OP-I activity. Moreover, the Km of OP-I was 0.33 mmol/L and Vmax was 66.7 mg/(mL ·min)as determined by kinetic studies.

Key words: Octopus vulgaris, protease, purification, characterization